Overview

This script was built using R 4.0.2 (Taking Off Again).

This tool filters reference and stress sites from Virginia and West Virginia EDAS databases, in this script we cast a “wide net” net on all the data (n=5292). This initial filter looks at 6 stress parameters that were available for the most sites in the database(s).

This is just step one of two step process, VDEQ and WVDEP biologists will review the results and help refine the reference and stress sites based on their site specific knowledge. WV DEP data was collected between 1999-2017, VDEQ data collections occurred from 2008-2020, but the majority was collected between 2012-2019.

Below is a breakdown of the sites that were available:

+ Total Sites Filtered = 5,292
+ VDEQ Sites = 3,279
+ WVDEP Sites = 2,013
+ Coastal Bioregion = 334
+ Piedmont Bioregion = 1,723
+ Mountain = 3,235

Least Disturbed (Ref) Filter Parameters:

  1. DO >8 mg/L
  2. pH >6,<9
  3. Sp Cond < 250 uS/cm
  4. TN <= 1 mg/L
  5. TP <= 0.02 mg/L
  6. Total Habitat > 150

Sites are assigned R1, R2, R3, or R4 based on the number parameters the site meets.

Stress Filters Parameters

  1. DO < 7 mg/L
  2. pH <6,>9
  3. Sp Cond > 500 uS/cm
  4. TN >= 2 mg/L
  5. TP >= 0.05 mg/L
  6. Total Habitat <= 120

Sites are assigned S1, S2, or S3 based on the number parameters the site meets.

Results

The first step of the process is to load all the sites and stress parameters into R. You can look at the first few rows below, note their are 17 columns at this point in the process.

After loading the biology sites with stressor paramaters, we then assign the sites a “Ref”, “Stress”, or “Fair” status based on each filter parameter as described in the overview. As an example, if a site has a Total Habitat score of 132 is would receive an assignment of “Fair”, it would need to score 150 or higher for “Ref” or 120 or lower to be “Stress”. After assigning all 5000+ sites a stress category for each parameter, the script counts the number of “Ref”, “Stress”, or “Fair” for each site. After counting each assignment, the sites receive the S1,S2,S3 or R1,R2,R3,R4 designations. See the first few sites in the table below, you can see the columns have expanded to 36 columns.

The next step of the process is to combine the reference and stress count together to find the sites with the highest stress and least stress. As an example, I combine sites with 3 stress or more (S1 sites) and sites with 1-3 reference filter (R4 sites). By adding sites that are S1 and R4, I am looking for sites that have a lot of disturbance and very few reference like qualities. These sites are then labeled “Highest Stress”. By combining sites with no stress S3 and sites the meet all reference filters R1, I find the sites with the least disturbance, they are assigned “BestRef”. I repeat combinations of the reference and stress results until all sites receive one of the eight categories. You can see that we now have 61 columns in the table.

Next we test the category assignment results by a subset of sites that have VSCI readily available (no WEST VADEP sites or Coastal Plain sites). A description of eight stress categories are found below the graph.

Reference and stress classification.

The histogram below showing the final count for each category of stress.

Map of Sites by Reference and Stress Classifications

Table of Results

Below is table of reference and stress classification totals by agency, bioregion, and regional office.

# Table of Stress Sites By EcoRegion

Below is table of stress classification totals by ecoregions (VDEQ data only).